MercurialEclipse
Update site: https://bitbucket.org/mercurialeclipse/update-site/raw/default/
Installation manual
As stated below (in comments) the name is MercurialEclipse. The name HgEclipse was a fork that Intland did and was later “merged” back again with MercurialEclipse, which moved around a bit between the current site, Google code and javaforge.com.